/*
 *		This Code Was Created By Lionel Brits & Jeff Molofee 2000
 *		A HUGE Thanks To Fredric Echols For Cleaning Up
 *		And Optimizing The Base Code, Making It More Flexible!
 *		If You've Found This Code Useful, Please Let Me Know.
 *		Visit My Site At nehe.gamedev.net
 *
 *		Trimmed into Xorg-crashing testcase by Brian Rogers <brian@xyzw.org>
 */
#include <windows.h>
#include <GL/gl.h>

static HDC		hDC=NULL;
static HGLRC		hRC=NULL;
static HWND		hWnd=NULL;
static HINSTANCE	hInstance;

static BOOL keys[256];
static BOOL fullscreen=FALSE;

LRESULT	CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

static int InitGL(void)
{
	glBlendFunc(GL_SRC_ALPHA,GL_ONE);
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	glClearDepth(1.0);
	glDepthFunc(GL_LEQUAL);
	glEnable(GL_DEPTH_TEST);
	glShadeModel(GL_SMOOTH);
	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
	glEnable(GL_LINE_SMOOTH);
	glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
	glEnable(GL_BLEND);
	glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glLineWidth(3);
	return TRUE;
}

static void KillGLWindow(void)
{
	if (fullscreen)
	{
		ChangeDisplaySettings(NULL,0);
		ShowCursor(TRUE);
	}

	if (hRC)
	{
		if (!wglMakeCurrent(NULL,NULL))
		{
			MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}

		if (!wglDeleteContext(hRC))
		{
			MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		}
		hRC=NULL;
	}

	if (hDC && !ReleaseDC(hWnd,hDC))
	{
		MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hDC=NULL;
	}

	if (hWnd && !DestroyWindow(hWnd))
	{
		MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hWnd=NULL;
	}

	if (!UnregisterClass("OpenGL",hInstance))
	{
		MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
		hInstance=NULL;
	}
}

static BOOL CreateGLWindow(const char* title, int width, int height, BOOL fullscreenflag)
{
	GLuint		PixelFormat;
	WNDCLASS	wc;
	DWORD		dwExStyle;
	DWORD		dwStyle;
	RECT		WindowRect;
	WindowRect.left=(long)0;
	WindowRect.right=(long)width;
	WindowRect.top=(long)0;
	WindowRect.bottom=(long)height;

	fullscreen=fullscreenflag;

	hInstance		= GetModuleHandle(NULL);
	wc.style		= CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
	wc.lpfnWndProc		= (WNDPROC) WndProc;
	wc.cbClsExtra		= 0;
	wc.cbWndExtra		= 0;
	wc.hInstance		= hInstance;
	wc.hIcon		= LoadIcon(NULL, IDI_WINLOGO);
	wc.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground	= NULL;
	wc.lpszMenuName		= NULL;
	wc.lpszClassName	= "OpenGL";

	if (!RegisterClass(&wc))
	{
		MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;
	}

	if (fullscreen)
	{
		DEVMODE dmScreenSettings;
		memset(&dmScreenSettings,0,sizeof(dmScreenSettings));
		dmScreenSettings.dmSize=sizeof(dmScreenSettings);
		dmScreenSettings.dmPelsWidth	= width;
		dmScreenSettings.dmPelsHeight	= height;
		dmScreenSettings.dmBitsPerPel	= 32;
		dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

		// Try To Set Selected Mode And Get Results.  NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.
		if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)
		{
			fullscreen=FALSE;
		}
	}

	if (fullscreen)
	{
		dwExStyle=WS_EX_APPWINDOW;
		dwStyle=WS_POPUP;
		ShowCursor(FALSE);
	}
	else
	{
		dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;
		dwStyle=WS_OVERLAPPEDWINDOW;
	}

	AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle);

	// Create The Window
	if (!(hWnd=CreateWindowEx(dwExStyle,
				"OpenGL",
				title,
				dwStyle | WS_CLIPSIBLINGS | WS_CLIPCHILDREN,
				0, 0,
				WindowRect.right-WindowRect.left,
				WindowRect.bottom-WindowRect.top,
				NULL,
				NULL,
				hInstance,
				NULL)))
	{
		KillGLWindow();
		MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;
	}

	static	PIXELFORMATDESCRIPTOR pfd =	// pfd Tells Windows How We Want Things To Be
	{
		sizeof(PIXELFORMATDESCRIPTOR),	// Size Of This Pixel Format Descriptor
		1,				// Version Number
		PFD_DRAW_TO_WINDOW |		// Format Must Support Window
		PFD_SUPPORT_OPENGL |		// Format Must Support OpenGL
		PFD_DOUBLEBUFFER,		// Must Support Double Buffering
		PFD_TYPE_RGBA,			// Request An RGBA Format
		32,				// Color Depth
		0, 0, 0, 0, 0, 0,		// Color Bits Ignored
		0,				// No Alpha Buffer
		0,				// Shift Bit Ignored
		0,				// No Accumulation Buffer
		0, 0, 0, 0,			// Accumulation Bits Ignored
		32,				// 32Bit Z-Buffer (Depth Buffer)
		0,				// No Stencil Buffer
		0,				// No Auxiliary Buffer
		PFD_MAIN_PLANE,			// Main Drawing Layer
		0,				// Reserved
		0, 0, 0				// Layer Masks Ignored
	};

	if (!(hDC=GetDC(hWnd)))
	{
		KillGLWindow();
		MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;
	}

	if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd)))
	{
		KillGLWindow();
		MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;
	}

	if(!SetPixelFormat(hDC,PixelFormat,&pfd))
	{
		KillGLWindow();
		MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;
	}

	if (!(hRC=wglCreateContext(hDC)))
	{
		KillGLWindow();
		MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;
	}

	if(!wglMakeCurrent(hDC,hRC))
	{
		KillGLWindow();
		MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;
	}

	ShowWindow(hWnd,SW_SHOW);
	SetForegroundWindow(hWnd);
	SetFocus(hWnd);

	if (!InitGL())
	{
		KillGLWindow();
		MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;
	}

	return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
	switch (uMsg)
	{
		case WM_ACTIVATE:
		{
			return 0;
		}

		case WM_SYSCOMMAND:
		{
			switch (wParam)
			{
				case SC_SCREENSAVE:
				case SC_MONITORPOWER:
				return 0;
			}
			break;
		}

		case WM_CLOSE:
		{
			PostQuitMessage(0);
			return 0;
		}

		case WM_KEYDOWN:
		{
			keys[wParam] = TRUE;
			return 0;
		}

		case WM_KEYUP:
		{
			keys[wParam] = FALSE;
			return 0;
		}
		case WM_MOUSEMOVE:
		{
			return 0;
		}
		case WM_SIZE:
		{
			return 0;
		}
	}

	// Pass All Unhandled Messages To DefWindowProc
	return DefWindowProc(hWnd,uMsg,wParam,lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
	MSG msg;
	BOOL done=FALSE;

	if (!CreateGLWindow("OpenGL Test",640,480,fullscreen))
	{
		return 0;
	}

	while(!done)
	{
		if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))
		{
			if (msg.message==WM_QUIT)
			{
				done=TRUE;
			}
			else
			{
				TranslateMessage(&msg);
				DispatchMessage(&msg);
			}
		}
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		SwapBuffers(hDC);
		if (keys[VK_ESCAPE])
			done = TRUE;
	}
	KillGLWindow();
	return msg.wParam;
}